INDIVIDUAL GENETIC VARIANTS MAY IMPACT RESULTS OF PSA TEST

QUT researcher A/Prof Jyotsna Batra and her team have found a certain variant in prostate specific antigen (PSA) gene can influence the structure, function and stability of PSA, and may impact on the accuracy of PSA testing, the main tool used to screen for prostate cancer. 

Following on from previous research which showed strong associations between single PSA gene variations and risk of prostate cancer, Dr Batra and her research team based at TRI have established that a particular genetic variation can cause changes to the structure, function and stability of PSA in vitro. Furthermore, cells that expressed this genetic variant showed less vigorous cell growth and decreased ability to migrate, compared to cells expressing the normal (wild-type) PSA protein by affecting glycosylation of the PSA protein.

Interestingly, the variant was associated with lower total PSA concentrations and high free/total PSA ratios, indicating that the clinically measured free/total PSA ratio may be impacted by the variant. This suggests that PSA testing in patients with the genetic variant may be less accurate.

“These results make us realise we need to consider how a person’s genetics can affect the outcomes of the PSA test” said Dr Batra.

“If we can take into account these variations, we may be able to increase the accuracy of the PSA test. For example, we incorporate genotype testing for these variations when interpreting results, or develop a new test to test for these changes to PSA structure.”

Article: Srinivasan, S. et al. (2019) Prostate cancer risk-associated single-nucleotide polymorphism affects prostate-specific antigen glycosylation and its function. Clinical Chemistry. 65:1, e1-e9. http://clinchem.aaccjnls.org/content/early/2018/12/10/clinchem.2018.29579